The present application relates to thermal media such as thermal paper rolls or thermal label rolls, and is particularly directed to self-cleaning thermal media and methods of manufacturing thereof.
A typical thermal paper roll 10 is shown in FIGS. 1 and 2. The thermal paper roll 10 comprises a continuous web 12 of material wound in a spiral around a core 14. The web 12 includes a substrate 16 (FIG. 2) having a front side 18 and a back side 20 opposite the front side. A thermal-sensitive coating 26 is disposed on the front side 18 of the substrate 16, and extends along a longitudinal running axis 24 (FIG. 1) of the web 12.
During use of the thermal paper roll 10 of FIGS. 1 and 2, the thermal paper roll is fed past a thermal print head of a direct thermal printer (not shown). The thermal print head provides heat to thermally image portions of the thermal-sensitive coating layer 26 to provide information, such as receipt information, on the thermally-imaged portions. A movable cutting blade of the printer then cuts the web 12 in cross-section at a location along the longitudinal running axis 24 to provide a printed receipt. Alternatively, the web 12 may be cut in cross-section by a user manually tearing it against a stationary cutting blade of the printer to provide a printed receipt.
Each time the thermal print head applies heat to thermally image portions of the thermal-sensitive coating layer 26, some residue is left behind on the thermal print head. This reduces the print quality of receipts as residue builds up over time on the thermal print head. In addition, the thermal paper roll 10 may produce a large amount of dust which can build up over time on the thermal print head. This also reduces the print quality of receipts as dust builds up over time on the thermal print head.
The buildup of residue and dust on the thermal print head requires an off-line cleaning regiment to be periodically followed in order to maintain print quality. Known cleaning regiments typically use separate cleaning supplies, and may use cleaning instruments such as cleaning cards and cleaning pens. A drawback in using known cleaning regiments is that compliance with these cleaning processes is difficult to enforce. It would be desirable to provide a way of cleaning a thermal print head and ensuring compliance with the cleaning process.